Cam means for knitting machine



Dec. 19, 1961 J. H. HILL CAM MEANS FOR KNITTING MACHINE:

Filed Dec. 19, 1958 R. m N W m JOHN HH/LL A N QRNEY Unite States Patentv Office 3,913,413 Patented Dec. 19, 1961 3,013,418 CAM MEANS FOR KNITTING MACHINE .lohn H. Hill, Wayne, Pa., assignor to Wildman Jacquard Co., Norristown, Pa., a corporation of Pennsylvania Filed Dec. 19, 195S, Ser. No. 781,530 Claims. (Cl. 66-57) This invention pertains to improvements in needle cam means for independent needle knitting machines.

An object of the invention is that of improving the cam action in knitting machines having accelerating levers or jacks so that more uniform stitches may be drawn.

A more specific object is that of so modifying and supplementing the usual mechanisms employed that extremely fast action may be imparted to needles throughout the major portion of their travel during their stitch forming function while at the terminal part of the stitch drawing movement, a slower and more precise draw is imparted more or less independently of the accelerating jacks.

Other objects will become apparent from the following more detailed disclosure.

In certain knitting problems it is more advantageous and at times almost essential to draw stitches as nearly independently as practicable. That is generally done by greatly accelerating the speed at which needles move, especially their stitch drawing motion. One mechanism usually employed to considerable advantage is that which includes accelerating jacks or levers pivoted to swing and having one end linked to the needle and being affected at either side of its pivot by cams one of which presses the jack downwardly or in a direction to draw the needle in the stitch forming direction and the other of which swings it reversely to move Athe needle to clearing and yarn taking positions. The leverage is such that small and not acutely inclined cams cause extended and rapid needle motions. These motions and mechanisms are rather well known and take different forms although they all involve the same general mode of operation.

One problem which does arise is that of a certain unevenness of stitch due to the fact that the cam motions are magnified and accelerated. If wear occurs at the swing jacks as it must after considerable usage, and with even minute variations in the tolerances between jacks, it becomes likely that the limit of the needle movement in drawing stitches may vary so that a serious lack of uniformity results.

According to the invention, an auxiliary or supplementary cam is positioned to act on the jacks at or adjacent the point at which they connect to their needles. This cam imparts a movement just slightly beyond that which is imparted by the rapid motion cams and is shaped to impart more or less the normal draw and, preferably at least, something less rapid than the motion imparted by the jacks.

In effect little speed is lost insofar as the whole cycle of forming a stitch goes, but the final stage is rendered more tractable and each stitch is formed as uniformly as practicable under all conditions.

The invention will be described by reference to a preferred embodiment thereof as illustrated in the accompanying ligures of drawing, wherein:

FIG. l is a section taken through a knitting machine to which the invention has been applied.

FlG. Z is a detail view showing the supplementary cam and the path of jack ends as they pass beneath it.

FIG. 3 is a plan view showing certain other details of the cam and its adjustment within its support.

FIG. 4 is a section showing the supplementary cam acting upon jacks ends at the terminal part of the stitch drawing movement of the needles.

Now referring to FIG. l, the invention may be applied to practically any knitting machine in which independently actuable needles are to be moved to take yarn, clear their latches of previously drawn loops and then form loops of the yarn just taken as the old loops are cast olf. Such machines are well known and comprise among other parts a base 10, ring 1l to which needle cylinder 12 is -attached and to which is also fixed or on which is formed a ring gear 13. The outer portion of ring 11 is borne for rotation in a bearing formed between a shouldered part 14 of the base 10 and the liange 1S of a cam section holder 16. A rotatable ring 17 in which are supported the swing jacks is actually clamped in position between the ring 11 and cylinder l2. Rings 11 and 17 and cylinder 12 rotate as a unit being driven in the l usual way by gearing meshing with gear 13.

The cylinder 12 is slotted and carries a plurality of needles 18, preferably of latch type, which have butts i9.

Sinkers 20 are slidably supported in the usual manner in a sinker head 21 fixed to the cylinder and are actuated conventionally by cams fixed in sinker cap 22. This cap is held stationary while sinkers are moved past it.

Such `a machine as is illustrated here is preferably used advantageously in the knitting of loop or terry cloth and for that purpose a plurality of so-called dummy needles j 23 are slidably supported in a dial 24 and cams (not shown) in a dial cap 25 act upon butts 26 to extend these dummy needles far enough so the terry or loop yarn may be drawn over them while a base yarn may be measured and drawn over sinkers. Of course, it is not necessary that the use of the needle actuating means herein described and claimed be employed in the knitting of pile or loop cloth and thus the dial and parts carried thereby need not be described in detail.

Each needle has associated for operation with it a swing jack or accelerator 27. These are somewhat angular in general prole having a pivot extension 28 rounded as shown, an outwardly directed arm 29 and an inwardly projecting arm 30 at the extremity of which a forked end 31 guided in the same slot as its respective needle connects to the butt of that needle. The connection forms a sort of knuckle joint and permits a relatively great angular movement for the jack.

These jacks are retained in radial slots in ring 32 which is circularlygrooved as shown to form a centr-al pivot recess for extensions 28 and to permit relative motion past cams 33 yand 33'. These latter are lixed to a cam plate in turn attached to support 16, these and parts to be described constituting a cam section. Cam 33 presses jack arms 3l) downwardly or in a stitch drawing direction while the complementary cam 33' presses arm 29 in a direction to raise needles through the jacks. Of course, slight working clearances have to be provided and while very effective and rapid needle action is realized, all with an easy cam action, there is more chance for non-uniformity between needles and thus fabric uniformity may suier somewhat due to the multiplying action of cams 33 and 33.

Applicant has remedied these objectionable characteristics without sacrificing those which are desired. In so doing a supplementary cam 34 is adjustably positioned to act upon the upper surfaces of the forked ends 31 of the jacks. This cam is shaped as shown in FIG. 2 and is screwed or otherwise held to or as a part of a stem or slide 35 of circular Section flattened to receive the cam. This stem is held in a circular guide bearing formed in a boss 36 or the like at the inner part of the cam plate 37. This has an open side as shown so the cam is prevented from turning. Springs 38 and 39 are set in holes in the glide boss and at the sides of the stern 35 and are compressed and retained by a pin 40 passed through a hole 3 crosswise of the stem and flattened at its ends to prevent withdrawal.

This cam thus tends to be raised by the springs, but is adjustably retained at proper elevation by a screw 41 threaded through a guide 42 screwed to the top of the plate 37. This screw has a rounded end 43 for contact with a beveled surface 43 at that side of the stem. A kuurled or other thumb wheel 44 or the like serves to aid in turning of the screw for adjustment. Any convenient means such `as a lock nut or bending the threaded section may be used to secure the adjustment in place. Turning the screw inwardly presses the cam downwardly to lengthen the switch and vice versa. Thus without any adjustment of cams 33 and 33 it is possible to change stitch length to a small degree.

Cam 34 has its effective surface cut at what may be termed a normal angle for an ordinary stitch cam. The flat surface following that may be of short or of extended length depending upon whether needles are to be held down or stitches relieved sooner or later.

Normally, slight clearance is provided between cams 33 and 33 `and jacks '30 in order to permit easy cam action. Additionally, a certain amount of wear will result after a period of use to increase that clearance and because of these two factors, accurate needle control at the termination of the switch drawing movement is diicult, especially because of the multiplying effect of the cams. The supplemental cam is effective upon the jack ends at the terminal part only of the stitch drawing movement of the needles at which time further slight clearance have been provided between the swing jacks and the rapid motion cams in order to render the latter ineffective, as noted in FIG. 4.

In action, needles are drawn down by the swing jacks as influenced by cam 33, but when a path or level 46 is reached these jacks will have arrived at substantially their limit of travel. The top, forked ends of the jacks or other appropriate or equivalent part thereof engages the surface 45 and then a slight draw down to a level 47 is effected. The amount of draw imparted by cam 34 is dependent upon its setting.

The present disclosure has reference to a rotary needle cylinder machine, but obviously, the opposite may be the case in which the cylinder is stationary while cams move past it and the needles and jacks. One knitting station only has been described here but it is to be understood that such mechanisms are usually a part of multifeed machines although not necessarily so.

While one embodiment of the invention has been disclosed, it is to be understood that the inventive concept may be carried out in a number of ways. This invention is, therefore, not to be limited to the precise details described, but is intended to embrace al1 variations and modifications thereof falling within the spirit of the in vention and the scope of the claims.

I claim:

1. In a knitting machine the combination of a needle bed, independently movable needles in said bed, accelerating swing jacks for said needles, and cams effective on said jacks for imparting to them needle operating movements throughout substantially the full extent of their travel, and a supplementary earn positioned closer to the needle bed than the cams rst mentioned and effective upon said jacks at that position and at the terminal part only of the switch drawing movement of the needles.

2. In a knitting machine the combination of a needle bed, independently movable needles in said bed, accelerating swing jacks for said needles, said jacks having pivot means about which they swing, cams at each side of said pivot means effective for moving said jacks to impart movements to the needles throughout substantially the full extent of their travel, and a supplementary cam positioned adjacent the needles in said bed and effective only at the last part of the needle and jack travel in their switch drawing movement to impart the terminal movement thereto after the cams first mentioned have become ineffective.

3. Mechanism as defined in claim 2 wherein said sup' plementary cam is mounted for adjustment to increase or decrease the extent to which it may affect jacks and their needles.

4. In a knitting machine the combination of a needle bed, independently movable needles in said bed, accelerating swing jacks for said needles, and fixed cams effective on said jacks for imparting to them needle operating movements and an adjustable supplementary cam positioned for affecting said jacks independently of said fixed cams and for rendering the stitch drawing motion of the jacks and needles variable as to extent.

5. In a knitting machine the combination of a needle bed, independently movable needles in said bed, accelerating swing jacks for said needles, and fixed cams effective on said jacks for imparting to them needle operating movements and an adjustable supplementary cam positioned for affecting said jacks independently of said fixed cams and for rendering the stitch drawing motion of the jacks and needles variable as to extent, said supplemental cam further being positioned to engage said jacks at a point closely adjacent said needle cylinder.

References Cited in the file of this patent UNITED STATES PATENTS 

